Recently, one of my clients, who had been invited for interviews at other institutions, was rejected from a medical school he wanted to attend. Much to his credit, he emailed the Dean of Admissions and wrote a cogent note expressing his interest and requesting a second consideration. Within twenty-four hours he had been offered an interview.
I'm not saying this is typical, but generally, I do recommend politely contacting institutions if you haven't heard anything or if you've been rejected from a school for which you think you are competitive.
Contact me for help.